What is a better aperture?

You'd be looking at the specs for lenses, not the camera. And what's better depends what type of photography and your budget.

Read some tutorials about aperture. Sign up for free tutorials at lynda.com or google aperature tutorials.

Aperture is measured in ‘f-stops’. You’ll often see them referred to here at Digital Photography School as f/number – for example f/2.8, f/4, f/5.6,f/8,f/22 etc. Moving from one f-stop to the next doubles or halves the size of the amount of opening in your lens (and the amount of light getting through).

The bigger the f/stop number the smaller the opening (that lets light in).

When you have the hang of that, look at prime lenses and zoom lenses and see their aperture choices and uses.

the bigger the aperture the better. a big aperture is a small value (2.8 is better than 4)

zoom lenses sometimes have like f/3.5 zoomed out, and then 5.6 zoomed in. that's usually a lower quality and a lower price. a zoom lens that has f/2.8 on every zoom level has a high quality, and an according price!

i worked with a 18-200mm f/3.5 - f/5.6 for a few years. working with a zoom range like that almost guarantees that your lens sucks on a quality level, but is very useful because of it's high zoom-windeangle range!

it's a question of what you're willing to shoot. portraits usually don't need flexibility, but quality! you also can't get these beautiful bokeh's with a 3.5 or 4 aperture. for me today, everything smaller than 2.8 is not worth buying, since i exclusively do portraits.

Generally speaking, the faster the lens (larger opening) the better. The camera has nothing to do with this. When you go to buy amateur lenses they are all pretty much middle of the road. Good lenses are very expensive and worth it. If you want good lenses, start with top of the line prime lenses not zoom lenses. A 50mm f1.4 is a great start at a reasonable price.